1. Field of the Invention
This invention relates to power splitters used with RF and microwave frequency signals in general and more particularly to a power splitter having a small package size that can be manufactured at low cost.
2. Description of the Related Art
Power splitters operating at frequencies up to 3 GHz have been made with ferrite transformers along with resistors and capacitors arranged around the ferrite transformers. When the frequency range starts below 10 MHz, two ferrite cores are necessary to achieve the desired electrical performance. The power splitter components typically use chip resistors and chip capacitors packaged on a circuit board.
Referring to FIG. 1, a prior art power splitter package is shown. Power splitter package 20 has a circuit board 21 upon which are mounted a pair of single core transformers 22 and 23. A chip resistor 24 and chip capacitor 25 are soldered onto circuit board 21 to one side of the transformers 22 and 23. Transformer wires 26 are attached to leads 27. A cover 28 is required to be placed over circuit board 21. The cover is required in order to protect the splitter components and to provide a surface for an automated surface mount machine to grasp and pickup the power splitter.
Unfortunately, placing the resistors and capacitors beside each transformer increases the size or footprint of the power splitter package and also complicates the assembly process. The mounting of the cover adds additional process steps and the expense of the cover. The use of the cover also reduces the ability to cool the power splitter. The cover causes the power splitter package to have a large height, which is undesirable in many applications. The cover can also trap liquids used during the manufacturing process possibly leading to increased corrosion or failure.
While power splitters have been used, they have suffered from being too large, difficult to assemble and are not easily used with automated surface mount equipment. A current unmet need exists for a power splitter that has a smaller size, can be assembled at a low cost and that can be used with automated surface mount equipment.